No, there should be not be an issue. On the contrary: scalability was one of the driving forces when we started moving from the Java client workstation to the browser based Webview. Webview acts as a proxy in front of the EM to cache data that is used by multiple users and thus move a part of the interactive workload away from the EM.
For the EM one Webview is handled the same as one workstation connection. So if you have 25 Webview users it is still a single connection to the EM and thus much less overhead than 25 workstations.
Ideally you would run multiple Webview servers that access the same APM cluster behind a load balancer. Just make sure that the Webview servers are properly sized but they are typically not very resource intensive. You might even run multiple Webview instances on different ports on the same server if you have enough resources. See WebView Requirements.
Did you know that you can also monitor Webview itself with a built-in agent?